the heat in my truck stopped getting warm and the Ford mechanic said it was the on 2005 Ford Explorer Sport Trac

blend door actuator and that it needed to be replaced.
He said they would need my truck for about a week and it would cost around $500.
Where is the blend door actuator on a 2005 ford sport trac?
Also does this have anything to do with the OBDII system?

Wow, thanks Greg's Orange Auto. Another question please, after getting my truck back from the mechanic, I went to get gas and the fuel gauge didn't go up to F. Several hours later it did. About 3 days later my fuel gauge stayed in the same spot and the engine light came on. I re-read the manual one of the suggestions was to fill the engine with good gas, which I did and the light went off. After driving around several days I noticed the fuel gauge was still on F, which I knew wasn't right. A day or 2 after that, the engine light came on again. Is the blend door actuator in the HVAC family & would problems with it affect the OBDII system?

there is a problem in the dash that they most likely caused, return and be nice but ask questions. they may not have the cluster plugged in all the way. the gauge doesn't know what grade gas you are using